Method os setting head-blocks of sawmills



UNITED sTATEs PATENT oEFIcE.

IRA ROBBINS, OF UNITYV ILLE, PENNSYLVANIA.

METHOD 0F SETTING HEAD-BLOCKS OF SAWIVIILLS.

Specicaton of Letters Patent No. 17,170, dated April 28, 1857.

To all whom t may concern:

Be it known that I, IEA RoBINs, of Unityville, in the county of Lycoming and Sta-te of Pennsylvania, have invented a new and useful Improvement in Sawmills; and I do hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawing, forming part of this specification, in which- Figure l is a top view of head block and setting mechanism. Fig. 2 is a side view of same.

Similar characters of reference in the several figures denote the same part.

The object `of my invention` is to effect the set of the end of the log, which is secured tO the head block slide, with greater celerity than is accomplished by the usual methods, the nature of the invention consisting in the peculiar combination of devices hereinafter to be set forth, for the aforesaid purpose.

In the drawing C is the carriage movable along the ways W W in the usual manner.

H is the head block, having the slide S to which the dogs are att-ached. This slide is moved by the rack a and pinion b (shown in drawing in red ink). The pinion b is upon the shaft c turned from the movement of shaft (Z through the gear wheels e and f. Upon the shaft cl is a ratchet wheel h, in the teeth of which the several pawls z', 7c, Z, act as will be hereinafter set forth. Upon the aforesaid shaft d, and outside of ratchet wheel L, is the bent lever m, so attached as to be capable of turning loosely upon the shaft, except when connected therewith through pawl z' and teeth of ratchet wheel 7L.. A weight n is attached to the extremity of the long arm of this lever.

Hanging loosely upon the shaft d, is the lever o, whose short arm has a projection which passes under the long arm of lever m, so that by pressure against the long arm of lever 0 lever m. will be turned about the shaft d, and its pawl be made to engage the teeth of ratchet la, at a distance proportional to the duration of pressure against lever 0.

also attached to a spring s by a cord 72. y

The lever L has an arm A, against which the stud t of the head block acts to move the lever L about its lfulcrum t. Behind the' lever catch s is a spring s, to keep the catch upon the end of spring s when it is drawn down by weight 1^.

The pawl is a lever attached to the head block at u, and so constructed that its long arm shall maintain the connection of the short arm with the ratchet teeth. The lifting of this long arm producing the disengagement ofthe teeth and pawl.

The operation of my improvement is as follows: As the carriage is near the termination of its gigging back, the long arm of lever 0, encounters a pin fv in one of the holes o of frame IUV, causing the long arm of lever mto the lifted, and the pawl i, consequently 4to engage the ratchet 7L, at a distance on its periphery proportional to the pressure exerted on lever 0 which is determined by the position of pin fv. Pawl Z prevents the ratchet from turning during this operation. Lever pawl c prevents the weight of lever m turning the ratchet in the opposite direction. The pawl z' has by this operation obtained such a position that when lever pawl 7c is removed weight a will instantly bring` lever m down upon its seat a, and the shaft d he turned the requisite distance for effecting the desired set. "As the carriage arrives at the end of its backward movement, and the saw is completely within slot a', stud t by pressing against arm A of lever L, moves that lever, causing weight r to b'e lifted so as to slacken cord p. Cord g is tightened, and draws upon lever catch s, so as to release spring s at the instant long arm of lever K is over said spring, causing the spring to lift long arm of said lever and effect `the release of the ratchet h. The set is thus given to the end of the log, at the proper time, with the utmost celerity. Weight 1" and spring '8 readjust the spring s for In testimony whereof, I have hereunto the next setting. signed my lname before tWo Subscribing I claim the combination of the lever catch Witnesses, s, spring s', cords 79 p and g, Weight r IRA ROBBINS. 5 stud and lever L, n connection With the Witnesses: Y e

lever lo, operating as, and for the purposes JOHN RICHART, described. ELI MENDENHALL. 

